Ok, I may get slammed for this, but here's my thought.

This was for your birthday. If this is the one sweet thing that you want for your birthday, eat ONE cookie. Give the rest away. Plan for the fact that on your birthday you go to maintanence level carbs - same as you might do on other holidays. If you plan for it, and plan the rest of your daily menu around the fact that you will have this one cookie, it is not a cheat. You are in control and are making an informed decision rather than an impulse reaction. In fact, if you want the cookie that badly, save it for the next day, and plan your carb levels accordingly. And if you don't want the whole cookie - eat the bite and enjoy it, toss the rest of the cookie, and estimate your carb intake from the bite. The whole "taste it then spit it out" thing seems to me to be more of an unhealthy practice than just eating the darn bite! All that guilt over a bite of cookie!

In my mind, cheats are when you lose control and somehow the food you eat starts controlling you instead of the other way around. This is a way of eating for the rest of your life, not a diet. There are times when you are going to want to eat a cookie. It is easier to cut them out completely, but if you want to really stay on this WOL you have to be able to make it work for you. And this means (at least for me) an occasional treat. However, it also means that I accept the consequences for my choice, and that I have to cut back on something else to have my cookie. And if you are going to eat the cookie and you've planned for your cookie - NO GUILT about it later! Fundamentally, it is just a cookie!

Just my opinion...